Pump, method for manufacturing pump, and refrigeration cycle device

ABSTRACT

A pump is provided that includes a molded stator having a substrate on which is mounted a magnetic-pole position detection element and that also includes a rotor having a rotor unit with one end thereof in an axial direction being opposed to the magnetic-pole position detection element and the other end thereof in the axial direction being provided with an impeller attachment unit. The rotor unit includes a magnet, a sleeve bearing, and a resin portion formed from a thermoplastic resin that is used for integrally molding the magnet and the sleeve bearing and that constitutes the impeller attachment unit. The magnet includes a plurality of through holes that each extend in the axial direction; and each of the through holes is embedded in the thermoplastic resin that constitutes a part of the resin portion.

FIELD

The present invention relates to a pump, a method for manufacturing apump, and a refrigeration cycle device.

BACKGROUND

A DC brushless motor has been proposed for use in a magnet motor pump.The magnet motor pump includes a rotor having a rotor magnet integrallyprovided in the impeller, a stator having a stator coil provided on anouter periphery side of the rotor, and a Hall element for detecting themagnetic poles of the rotor magnet arranged inside the stator (see, forexample, Patent Literature 1).

CITATION LIST Patent Literature

Patent Literature 1: Japanese Utility Model Laid-open Publication No.H05-23784

SUMMARY Technical Problem

There is a problem however with the pump used with the magnet pump motordescribed in the above Patent Literature 1 in that, because the outerperipheral surface of the rotor magnet is covered with a thermoplasticresin, the distance between the stator and the rotor magnet is increasedand thus the performance of the pump is possibly reduced.

The present invention has been achieved in view of the above problem,and an objective of the present invention is to provide a pump that canprevent magnets from cracking due to the thermal shock associated with acold/hot water cycle without the outer peripheral surface of the magnetbeing covered with resin, to provide a method for manufacturing thepump, and to provide a refrigeration cycle device including the pump.

Solution to Problem

The present invention is made to solve the problem and achieve theobjective mentioned above and is relates to a pump that includes: anannular molded stator having a substrate upon which is mounted amagnetic-pole position detection element; and a rotor having an annularrotor unit rotatably housed in a cup-shaped partition component, withone end thereof in an axial direction opposing the magnetic-poleposition detection element and with the other end thereof in the axialdirection being provided with an impeller attachment unit to which animpeller is attached. The rotor unit includes an annular magnet, asleeve bearing provided inside of the magnet, and a resin portion formedfrom a thermoplastic resin from which an integral molding is made forthe magnet and the sleeve bearing and that constitutes the impellerattachment unit, the magnet includes a plurality of through holes, eachextending in the axial direction between an end face on a side of themagnetic-pole position detection element and an end face on a side ofthe impeller attachment unit, and each of the through holes is embeddedin the thermoplastic resin that constitutes a part of the resin portion.

Advantageous Effects of Invention

According to the present invention, a plurality of through holes, eachextending in an axial direction, is provided in a magnet thatconstitutes a rotor unit, and each of the through holes is embedded in athermoplastic resin when they are integrally molded. Therefore, themagnet is firmly held by the thermoplastic resin and is prevented fromcracking due to the thermal shock associated with a cold/hot water cyclewithout the outer peripheral surface of the magnet being covered withthe resin.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a configuration diagram of a heat-pump type water heateraccording to a first embodiment.

FIG. 2 is an exploded perspective view of a pump 10 according to thefirst embodiment.

FIG. 3 is a perspective view of a molded stator 50.

FIG. 4 is a cross-sectional view of the molded stator 50.

FIG. 5 is an exploded perspective view of a stator assembly 49.

FIG. 6 is an exploded perspective view of a pump unit 40.

FIG. 7 is a cross-sectional view of the pump 10.

FIG. 8 is a perspective view of a casing 41 viewed from a side of ashaft support portion 46.

FIG. 9 is a cross-sectional view of a rotor unit 60 a (specifically, across-sectional view on arrow A-A in FIG. 11).

FIG. 10 is a view of the rotor unit 60 a viewed from a side of animpeller attachment unit.

FIG. 11 is a view of the rotor unit 60 a viewed from an opposite side tothe side of the impeller attachment unit.

FIG. 12 is an enlarged cross-sectional view of a sleeve bearing 66.

FIG. 13 is a cross-sectional view of a resin magnet 68 (specifically, across-sectional view on arrow B-B in FIG. 14).

FIG. 14 is a view of the resin magnet 68 viewed from the side of aprotrusion 68 a (the side of the impeller attachment unit).

FIG. 15 is a view of the resin magnet 68 viewed from an opposite side tothe side of the protrusion 68 a.

FIG. 16 is a perspective view of the resin magnet 68 viewed from theside of the protrusion 68 a.

FIG. 17 is a perspective view of the resin magnet 68 viewed from theopposite side to the side of the protrusion 68 a.

FIG. 18 is a perspective view of the rotor unit 60 a viewed from theside of the impeller attachment unit.

FIG. 19 is a perspective view of the rotor unit 60 a viewed from anopposite side to the side of the impeller attachment unit.

FIG. 20 illustrates a manufacturing process of the pump 10.

FIG. 21 is a conceptual diagram illustrating a circuit in arefrigeration cycle device that uses a refrigerant-water heat exchanger.

FIG. 22 is a sectional view of the rotor unit 60 a according to a secondembodiment.

FIG. 23 is a sectional view of the resin magnet 68 according to thesecond embodiment.

DESCRIPTION OF EMBODIMENTS

Exemplary embodiments of a pump, a method for manufacturing a pump, anda refrigeration cycle device according to the present invention will beexplained below in detail with reference to the accompanying drawings.The present invention is not limited to the embodiments.

First Embodiment

In the following descriptions, an outline of a heat-pump type waterheater as an example of application of the pump according to the presentembodiment is described first, and details of the pump are given next.

FIG. 1 is a configuration diagram of a heat-pump type water heateraccording to the present embodiment. As illustrated in FIG. 1, aheat-pump type water heater 300 includes a heat pump unit 100, a tankunit 200, and an operating unit 11 that is used when a user performs adrive operation and the like.

In FIG. 1, the heat pump unit 100 includes a compressor 1 (for example,a rotary compressor or a scroll compressor) that compresses arefrigerant; a refrigerant-water heat exchanger 2 in which heat isexchanged between the refrigerant and water; a decompression device 3that decompresses and expands the high-pressure refrigerant; anevaporator 4 that evaporates a low-pressure two-phase refrigerant; arefrigerant pipe 15 that connects the compressor 1, therefrigerant-water heat exchanger 2, the decompression device 3, and theevaporator 4 in a circular circuit; a pressure detection device 5 thatdetects discharge pressure of the compressor 1; a fan 7 that blows airinto the evaporator 4; and a fan motor 6 that drives the fan 7. Thecompressor 1, the refrigerant-water heat exchanger 2, the decompressiondevice 3, the evaporator 4, and the refrigerant pipe 15 that connectsthese in a circular circuit constitute a refrigerant circuit.

The heat pump unit 100 includes a boiling-point temperature detectionunit 8 of the refrigerant-water heat exchanger 2; a feed-watertemperature detection unit 9 of the refrigerant-water heat exchanger 2;and an ambient-air temperature detection unit 17, as a temperaturedetection unit.

The heat pump unit 100 also includes a heat-pump-unit control unit 13.The heat-pump-unit control unit 13 receives signals from the pressuredetection device 5, the boiling-up temperature detection unit 8, thefeed-water temperature detection unit 9, and the ambient-air temperaturedetection unit 17 and executes control of the number of revolutions ofthe compressor 1, control of the opening degree of the decompressiondevice 3, and control of the number of revolutions of the fan motor 6.

The tank unit 200 includes a hot water tank 14 that stores hot waterheated by exchanging heat with the high-temperature and high-pressurerefrigerant in the refrigerant-water heat exchanger 2; abathwater-reheating heat exchanger 31 that reheats bathwater; abathwater circulating device 32 connected to the bathwater-reheatingheat exchanger 31; a pump 10 being a hot-water circulating devicearranged between the refrigerant-water heat exchanger 2 and the hotwater tank 14; a hot-water circulating pipe 16 that connects therefrigerant-water heat exchanger 2 and the hot water tank 14; a mixingvalve 33 connected to the refrigerant-water heat exchanger 2, the hotwater tank 14, and the bathwater-reheating heat exchanger 31; and abathwater reheating pipe 37 that connects the hot water tank 14 and themixing valve 33. The refrigerant-water heat exchanger 2, the hot watertank 14, the pump 10, and the hot-water circulating pipe 16 constitute awater circuit.

The tank unit 200 also includes an in-tank water-temperature detectionunit 34; a reheated water-temperature detection unit 35 that detects thewater temperature after it has passed through the bathwater-reheatingheat exchanger 31; and a mixed water-temperature detection unit 36 thatdetects the water temperature after it has passed through the mixingvalve 33, as a temperature detection unit.

The tank unit 200 further includes a tank-unit control unit 12. Thetank-unit control unit 12 receives signals from the in-tankwater-temperature detection unit 34, the reheated water-temperaturedetection unit 35, and the mixed water-temperature detection unit 36, inorder to execute control of the number of revolutions of the pump 10 andopening/closing control of the mixing valve 33. The tank unit 200further performs sending and receiving of signals to and from theheat-pump-unit control unit 13 and to and from the operating unit 11.

The operating unit 11 is a remote controller or an operation panelincluding a switch for a user to set the temperature setting of the hotwater or to instruct hot water to be supplied.

In FIG. 1, a normal boiling operation in the heat-pump type water heater300 configured as described above is explained. When a boiling operationinstruction from the operating unit 11 or the tank unit 200 istransmitted to the heat-pump-unit control unit 13, the heat pump unit100 performs a boiling operation.

The heat-pump-unit control unit 13 executes control of the number ofrevolutions of the compressor 1, control of the opening degree of thedecompression device 3, and control of the number of revolutions of thefan motor 6 on the basis of the detection values of the pressuredetection device 5, the boiling-up temperature detection unit 8, and thefeed-water temperature detection unit 9.

Further, the detection value detected by the boiling-up temperaturedetection unit 8 is transferred between the heat-pump-unit control unit13 and the tank-unit control unit 12; and the tank-unit control unit 12controls the number of revolutions of the pump 10 so that thetemperature detected by the boiling-up temperature detection unit 8becomes a target boiling-up temperature.

In the heat-pump type water heater 300 controlled as described above,the high-temperature and high-pressure refrigerant discharged from thecompressor 1 reduces its temperature, while dissipating heat to a watersupply circuit. The high-temperature and high-pressure refrigerant,which has dissipated heat and passed through the refrigerant-water heatexchanger 2, is decompressed by the decompression device 3. Therefrigerant having passed through the decompression device 3 flows intothe evaporator 4, and absorbs heat from ambient-air. The low-pressurerefrigerant having been discharged from the evaporator 4 is drawn intothe compressor 1 to repeat circulation, thereby forming a refrigerationcycle.

Meanwhile, water in a lower part in the hot water tank 14 is guided tothe refrigerant-water heat exchanger 2 driven by the pump 10 which isthe hot-water circulating device. Water is heated by heat dissipationfrom the refrigerant-water heat exchanger 2; and the heated hot waterpasses through the hot-water circulating pipe 16 and is returned to anupper part of the hot water tank 14 and stored.

As explained above, in the heat-pump type water heater 300, the pump 10is used as the hot-water circulating device that circulates hot waterthrough the hot-water circulating pipe 16 between the hot water tank 14and the refrigerant-water heat exchanger 2.

The pump 10 according to the present embodiment is explained next. FIG.2 is an exploded perspective view of the pump 10 according to thepresent embodiment.

As illustrated in FIG. 2, the pump 10 includes a pump unit 40 thatabsorbs and discharges water by the revolution of the rotor (describedlater); a molded stator 50 that drives the rotor; and tapping screws 160that fasten the pump unit 40 to the molded stator 50. In an exampleillustrated in FIG. 2, the number of tapping screws 160 is, for example,five. However, the number of tapping screws is not limited thereto.

The pump 10 is assembled by fastening five tapping screws 160 to pilotholes 84 of a pilot hole component 81 (for details, refer to FIG. 5illustrated later) embedded in the molded stator 50 via screw holes 44 aformed in a boss 44 of the pump unit 40.

In FIG. 2, a casing 41, an intake 42, a discharge outlet 43, acup-shaped partition component 90, a lead wire 52, a mold resin 53, astator iron core 54, and a pump-unit installation surface 63 areillustrated but they do not appear in the configurations explainedabove. These elements are explained later.

The configuration of the molded stator 50 is explained first withreference to FIGS. 3 to 5. FIG. 3 is a perspective view of the moldedstator 50, FIG. 4 is a cross-sectional view of the molded stator 50, andFIG. 5 is an exploded perspective view of a stator assembly 49.

The molded stator 50 is acquired by molding the stator assembly 49 byusing the mold resin 53 (FIGS. 3 and 4).

On one end face of the molded stator 50 in an axial direction,specifically, on an end face on the side of the pump unit 40 (refer alsoto FIG. 2), a flat pump-unit installation surface 63 is provided alongan outer peripheral edge thereof.

A leg part 85 (refer to FIGS. 4 and 5) of the pilot hole component 81 isaxially embedded at five places in the pump-unit installation surface63. The leg part 85 is, for example, a substantially columnar resinmolded component. At the time of mold forming by using the mold resin53, one end face of the leg part 85 (the end face on the side of thepump unit 40) becomes a die pressing part 82 of a molding die (refer toFIG. 4). Therefore, the pilot hole component 81 is exposed in a form ofbeing embedded inward from the pump-unit installation surface 63 by apredetermined distance. The exposed parts are the die pressing part 82and the pilot hole 84 for the tapping screw 160.

The lead wire 52 pulled out from the stator assembly 49 is pulled out tothe outside from a vicinity of the axial end face of the molded stator50 opposite to the side of the pump unit 40.

Axial positioning of the molded stator 50 by the mold resin 53 (forexample, thermosetting resin) at the time of mold forming is performedby axial end faces of a plurality of protrusions 95 a, which are formedin a substrate pressing component 95 (refer to FIG. 5), functioning as apressing part of an upper die. Therefore, the axial end faces (diepressing surfaces) of the protrusions 95 a are exposed (not illustrated)from the axial end face of the molded stator 50 on a side of a substrate58.

An axial end face of an insulation part 56 on an opposite side to a wireconnection (on the side of the pump unit 40) becomes a die pressing partof a lower die. Accordingly, from the axial end face of the moldedstator 50 on the opposite side to the substrate 58, the end face of theinsulation part 56 on the opposite side to the wire connection isexposed (not illustrated).

Radial positioning of the molded stator 50 at the time of mold formingis made by fitting an inner periphery of the stator iron core to thedie. Therefore, tip ends of teeth (the inner periphery) of the statoriron core 54 are exposed to the inner periphery of the molded stator 50illustrated in FIG. 3.

The internal configuration of the molded stator 50, that is, theconfiguration or the like of the stator assembly 49 is described next.

As illustrated in FIG. 5, the stator assembly 49 includes a stator 47and a pilot hole component 81. As illustrated in FIGS. 4 and 5, thestator 47 includes the lead wire 52, the stator iron core 54 providedwith grooves 54 a, the insulation part 56, a coil 57, an IC 58 a, a Hallelement 58 b, the substrate 58, a terminal 59, a lead-wire leadingcomponent 61, and a substrate pressing component 95. The pilot holecomponent 81 includes leg parts 85, protrusions 83 and 85 a provided inthe leg parts 85, and a connection part 87.

The stator assembly 49 is manufactured in the procedure described below.

(1) An electromagnetic steel plate having a thickness of, for example,0.1 millimeter to 0.7 millimeter is punched in a belt-like form, and theannular stator iron core 54 laminated by swaging, welding, or bonding ismade from the electromagnetic steel plate. The stator iron core 54 has aplurality of teeth. Tip ends of the teeth of the stator iron core 54 areexposed to the inner periphery of the molded stator 50 illustrated inFIG. 3. The stator iron core 54 illustrated here has, for example, 12teeth connected with thin connection parts. Therefore, in FIG. 3, thetip ends of the teeth of the stator iron core 54 are exposed at 12positions. However, only five teeth of the 12 teeth are viewed in FIG.3.(2) The insulation part 56 is applied to the teeth of the stator ironcore 54. The insulation part 56 is formed integrally with or separatelyto the stator iron core 54 by using, for example, a thermoplastic resinsuch as PBT (polybutylene terephthalate).(3) A concentratedly wound coil 57 (refer to FIG. 4) is wound around theteeth applied with the insulation part 56. By connecting 12concentratedly wound coils 57, three-phase single Y-connection windingsare formed.(4) Because of the three-phase single Y-connection, terminals 59 (referto FIG. 4, supply terminals to which power is supplied, and a neutralterminal) to which the coils 57 (refer to FIG. 4) of respective phases(a U phase, a V phase, and a W phase) are connected are assembled on theconnection side of the insulation part 56. There are three supplyterminals and one neutral terminal.(5) The substrate 58 is attached to the insulation part 56 on theconnection side (on the side where the terminals 59 are assembled). Thesubstrate 58 is held between the substrate pressing component 95 and theinsulation part 56. An electronic component is mounted on the substrate58, for example, the IC 58 a (drive element) that drives a motor (forexample, a brushless DC motor), the Hall element 58 b that detects theposition of the rotor 60 (refer to FIG. 4, a magnetic-pole positiondetection element), and the like are provided thereon. Because the IC 58a is mounted on the side of the substrate pressing component 95 of thesubstrate 58, it is illustrated in FIG. 5. However, the Hall element 58b is hidden and not seen in FIG. 5, because it is mounted on theopposite side to the IC 58 a. Further, the substrate 58 is attached withthe lead-wire leading component 61 that leads out the lead wire 52 in anotched portion near the outer periphery thereof.(6) The substrate 58 attached with the lead-wire leading component 61 isfixed to the insulation part 56 by the substrate pressing component 95;and the pilot hole component 81 is assembled on the stator 47 to whichthe terminals 59 and the substrate 58 are soldered, thereby completingthe stator assembly 49 (refer to FIG. 5).

The configuration of the pilot hole component 81 is explained next withreference to FIG. 5. The pilot hole component 81 is formed by molding athermoplastic resin such as PBT (polybutylene terephthalate).

As illustrated in FIG. 5, the pilot hole component 81 is configured bycircularly connecting a plurality (for example, five) of leg parts 85 ina substantially columnar shape with the thin connection part 87. The legpart 85 is provided with the pilot hole 84 to be screwed into with thetapping screw 160 (refer to FIG. 2). The leg part 85 has a taperedshape, in which the leg part 85 becomes thicker from the exposed endface (the die pressing part 82 and the end face of the protrusion 83)toward the axial center. By having such a tapered shape, the pilot holecomponent 81 is effectively prevented from falling off after performingmold forming with the stator 47.

The pilot hole component 81 includes the plurality of protrusions 85 aon the outer periphery of the leg part 85 for preventing rotation. Inthe example illustrated in FIG. 5, four protrusions 85 a are provided onthe outer periphery of the leg part 85. The protrusion 85 a is formed toextend in a height direction (an axial direction) of the leg part 85with a predetermined circumferential width. Further, the protrusion 85 aprotrudes from an outer peripheral surface of the leg part 85 by arequired predetermined dimension in order to prevent the pilot holecomponent 81 from being rotated. The pilot hole component 81 can be setto the molding die in the first attempt by connecting the substantiallycolumnar leg parts 85 with the thin connection part 87, thereby enablingthe machining cost to be reduced.

By providing a plurality of claws (not illustrated) for assembling thepilot hole component 81 on the stator 47 in the connection part 87 ofthe pilot hole component 81 and latching the claws of the pilot holecomponent 81 into the grooves 54 a formed on the outer periphery of thestator iron core 54 of the stator 47, the stator 47 and the pilot holecomponent 81 can be set to the molding die in the first attempt, therebyenabling the machining cost to be reduced.

When the stator assembly 49 is mold-formed by the mold resin 53 afterlatching the pilot hole component 81 to the stator 47, the axialpositioning of the pilot hole component 81 is performed by holding thedie pressing part 82 and the protrusions 83 of the pilot hole component81 by the mold forming die.

An outer diameter of the die pressing part 82 can be set smaller than anouter diameter of an opening-side end face of the pilot hole component81 (refer to FIG. 4). Thus, the end face of the pilot hole component 81of a portion excluding the die pressing part 82 is covered with the moldresin 53. Therefore, because the opposite end face of the pilot holecomponent 81 is covered with the mold resin 53, exposure of the pilothole component 81 is suppressed, thereby enabling the quality of thepump 10 to be improved.

The molded stator 50 is obtained by integrally molding the pilot holecomponent 81 assembled on the stator 47 by the mold resin 53. In thiscase, the pilot holes 84 are molded so as to be exposed. By andassembling and fastening the pump unit 40 and the molded stator 50 tothe pilot hole 84 with the tapping screws 160 via the screw holes 44 aformed in the pump unit 40, the pump unit 40 and the molded stator 50can be firmly assembled together (refer to FIG. 2).

The configuration of the pump unit 40 is to be explained next withreference to FIGS. 6 to 8. FIG. 6 is an exploded perspective view of thepump unit 40, FIG. 7 is a cross-sectional view of the pump 10, and FIG.8 is a perspective view of the casing 41 viewed from a side of a shaftsupport portion 46. The pump unit 40 includes the following elements:

(1) Casing 41 that has the intake 42 and the discharge outlet 43 offluid and houses an impeller 60 b of the rotor 60 therein: The casing 41is molded by using a thermoplastic resin, for example, PPS(polyphenylene sulfide). A boss 44 with a screw hole 44 a, which is usedat the time of assembling the pump unit 40 and the molded stator 50, isprovided at five positions.(2) Thrust bearing 71: The material of the thrust bearing 71 is aceramic, for example, alumina. The rotor 60 is pressed against thecasing 41 via the thrust bearing 71, due to a pressure difference actingon the both sides of the impeller 60 b of the rotor 60 during theoperation of the pump 10. Therefore, a thrust bearing made of a ceramicis used as the thrust bearing 71 to ensure wear resistance and slidingproperties.(3) Rotor 60: The rotor 60 includes a rotor unit 60 a and the impeller60 b. In the rotor unit 60 a, a ring-shaped (cylindrical or annular)resin magnet 68 (an example of a magnet) molded by using a pellet formedby kneading a magnetic powder, for example, ferrite powder and resin anda cylindrical sleeve bearing 66 (for example, made of carbon) providedinside of the resin magnet 68 are integrated at a resin portion 67 madeof such as, for example, PPE (polyphenylene ether) (refer to FIG. 9explained later). The impeller 60 b is a resin molded product of, forexample, PPE (polyphenylene ether). The rotor unit 60 a and the impeller60 b are bonded by, for example, ultrasonic welding.(4) Shaft 70: The material of the shaft 70 (a rotary shaft) is aceramic, for example, alumina, or SUS. Because the shaft 70 slides withthe sleeve bearing 66 provided in the rotor 60, a material such as aceramic or SUS is selected so as to ensure the wear resistance andsliding properties. One end of the shaft 70 is inserted into a shaftsupport portion 94 of the cup-shaped partition component 90; and theother end of the shaft 70 is inserted into the shaft support portion 46of the casing 41. Therefore, the one end of the shaft 70 to be insertedinto the shaft support portion 94 is inserted therein so as not torotate with respect to the shaft support portion 94. Therefore, the oneend of the shaft 70 is substantially D shaped, which is obtained bycutting a part of a circular form by a predetermined length (in an axialdirection). A hole in the shaft support portion 94 has a shape matchedwith the shape of the one end of the shaft 70. Further, the other end ofthe shaft 70 to be inserted into the shaft support portion 46 is alsosubstantially D shaped, which is obtained by cutting a part of acircular form by a predetermined length (in an axial direction), andthus the shaft 70 has a symmetrical shape in a lengthwise direction.However, the other end of the shaft 70 is inserted rotatably into theshaft support portion 46. The reason why the shaft is symmetrical in thelengthwise direction is because, at the time of inserting the shaft 70into the shaft support portion 94, it is possible to assemble it withouttaking into consideration whether the direction is up or down (refer toFIG. 6).(5) O-ring 80: The material of the O-ring 80 is, for example, EPDM(ethylene-propylene-diene rubber). The O-ring 80 seals the casing 41from the cup-shaped partition component 90 of the pump unit 40. In apump mounted on a hot water dispenser, heat resistance and long life arerequired for sealing the piping. Therefore, the material such as EPDM isused to ensure the resistance properties.(6) Cup-shaped partition component 90: The cup-shaped partitioncomponent 90 is molded by using a thermoplastic resin, for example, PPE(polyphenylene ether). The cup-shaped partition component 90 includes acup-shaped partition wall portion 90 a that is a joint with the moldedstator 50, and a flange portion 90 b. The cup-shaped partition wallportion 90 a is formed of a circular bottom and a cylindrical partitionwall. The shaft support portion 94, into which the one end of the shaft70 is inserted, is provided in a standing condition substantially at thecenter on an internal surface of the bottom of the cup-shaped partitionwall portion 90 a. On an external surface of the bottom of thecup-shaped partition wall portion 90 a, a plurality of ribs 92 areradially formed in a radial direction. A plurality of reinforcing ribs(not illustrated) are radially formed on the flange portion 90 b in theradial direction. The flange portion 90 b also includes an annular rib(not illustrated) housed in the pump-unit installation surface 63 of thepump unit 40. The flange portion 90 b is formed with a hole 90 d,through which the tapping screw 160 passes, at five positions. Acircular O-ring housing groove 90 c for housing the O-ring 80 is formedon a surface of the flange portion 90 b on the side of the casing 41.

The pump 10 is constructed by fixing the casing 41 to the cup-shapedpartition component 90 after installing the O-ring 80 in the cup-shapedpartition component 90 and installing the shaft 70, the rotor 60, andthe thrust bearing 71 in the cup-shaped partition component 90 toconstruct the pump unit 40; and further fixing the pump unit 40 to themolded stator 50 by the assembly tapping screws 160 and the like.

By fitting the ribs 92 provided on the bottom of the cup-shapedpartition component 90 to the groove (not illustrated) in the moldedstator 50, circumferential positioning of the pump unit 40 and themolded stator 50 is performed.

The rotor 60 is housed inside of the cup-shaped partition wall portion90 a. The rotor 60 is fitted to the shaft 70 inserted into the shaftsupport portion 94 of the cup-shaped partition component 90. Therefore,to ensure concentricity between the molded stator 50 and the rotor 60,it is better to keep the gap between an inner circumference of themolded stator 50 and an outer circumference of the cup-shaped partitionwall portion 90 a as small as possible. For example, the gap is set tobe about 0.02 millimeter to 0.06 millimeter.

However, if the gap between the inner circumference of the molded stator50 and the outer circumference of the cup-shaped partition wall portion90 a is too small, the escape route for air becomes narrow when thecup-shaped partition wall portion 90 a is inserted into the innercircumference of the molded stator 50, thereby making it difficult toinsert the cup-shaped partition component 90.

FIG. 9 is a cross-sectional view of the rotor unit 60 a (specifically, across-sectional view along arrow A-A in FIG. 11); FIG. 10 is a view ofthe rotor unit 60 a viewed from a side of an impeller attachment unit;FIG. 11 is a view of the rotor unit 60 a viewed from an opposite side tothe side of the impeller attachment unit; and FIG. 12 is an enlargedcross-sectional view of the sleeve bearing 66.

The rotor unit 60 a is explained with reference to FIGS. 9 to 12. Asillustrated in FIGS. 9 to 12, the rotor unit 60 a includes at least thefollowing elements:

(1) Resin magnet 68;(2) Sleeve bearing 66; and(3) Resin portion 67. The resin portion 67 is constituted by athermoplastic resin, for example, PPE (polyphenylene ether). Theimpeller attachment unit 67 a, to which the impeller 60 b is attached,is formed in the resin portion 67. The resin magnet 68 and the sleevebearing 66 are integrally molded by using the resin portion 67.

The resin magnet 68 is substantially ring shaped (cylindrical or annularshape), and is molded by using the pellet formed by kneading it with amagnetic powder, for example, ferrite powder and resin.

The sleeve bearing 66 (for example, made of carbon) is provided insideof the resin magnet 68. The sleeve bearing 66 has a cylindrical shape.The sleeve bearing 66 is fitted to the shaft 70 which is assembled onthe cup-shaped partition component 90 of the pump 10 to rotate.Therefore, the sleeve bearing 66 is fabricated by a material suitablefor the bearing, for example, a thermoplastic resin such as PPS(polyphenylene sulfide) added with sintered carbon or carbon fiber, or aceramic. The sleeve bearing 66 is provided with a drawing-out taper (notillustrated), which has an outer diameter decreasing with distance froma substantially axial center toward the opposite ends, and is providedwith, for example, a plurality of semispherical protrusions 66 a (referto FIG. 12) on an outer periphery, which prevent the rotationsubstantially at an axial center.

A depression 67 b is formed in a portion contacting to an end face ofthe resin magnet 68 on the side of the impeller attachment unit of theresin portion 67, corresponding to a magnet pressing part (notillustrated) provided on the upper die of the resin molding die. Thedepression 67 b is formed substantially at the center in a radialdirection in the example illustrated in

FIG. 9. The depression 67 b is formed at a position substantially facingthe protrusion 68 a of the resin magnet 68 in the axial direction.

As illustrated in FIG. 10, a plurality of impeller positioning holes 67c for attaching the impeller 60 b are made in the impeller attachmentunit 67 a. For example, three impeller positioning holes 67 c are formedsubstantially at a regular interval in the circumferential direction.The impeller positioning holes 67 c penetrate the impeller attachmentunit 67 a. The impeller positioning holes 67 c are respectively formedon a radial extension line in the middle of two protrusions 68 a (referto FIG. 10) among the three protrusions of the resin magnet 68.

Furthermore, as illustrated in FIG. 10, for example, three gates 67 e,which are to be used when the rotor unit 60 a is molded by using thethermoplastic resin (the resin portion 67), are respectively formedsubstantially at a regular interval in the circumferential direction.The respective gates 67 e are formed on the radial extension line of theprotrusions of the resin magnet 68, and inside relative to the impellerpositioning holes 67 c.

Notches 67 d to be fitted to a positioning protrusion (not illustrated)provided in the lower die of the resin molding die are formed in aportion of the resin portion 67 formed by contacting to an innerperiphery of the resin magnet 68 opposite to the side of the impellerattachment unit 67 a (refer to FIGS. 9 and 11). The notch 67 d areformed at four positions substantially with an interval of 90 degrees inthe example illustrated in FIG. 11. A plurality (eight in the exampleillustrated in FIG. 11) of protrusions 68 e, being a part of the resinmagnet 68, are exposed from the resin portion 67 (refer to FIG. 11).

A plurality of through holes 69, each extending in the axial directionand being provided in the resin magnet 68, and the inside of each of thethrough holes 69 is filled with the thermoplastic resin. That is, thethermoplastic resin in the through holes 69 constitutes a part of theresin portion 67.

FIG. 13 is a cross-sectional view of a resin magnet 68 (specifically, across-sectional view in the direction of arrow B-B in FIG. 14); FIG. 14is a view of the resin magnet 68 viewed from the side of a protrusion 68a (the side of the impeller attachment unit); FIG. 15 is a view of theresin magnet 68 viewed from an opposite side to the side of theprotrusion 68 a; FIG. 16 is a perspective view of the resin magnet 68viewed from the side of the protrusion 68 a; and FIG. 17 is aperspective view of the resin magnet 68 viewed from the opposite side tothe side of the protrusion 68 a. FIG. 18 is a perspective view of therotor unit 60 a viewed from the side of the impeller attachment unit;and FIG. 19 is a perspective view of the rotor unit 60 a viewed from anopposite side to the side of the impeller attachment unit.

The configuration of the resin magnet 68 is explained referring to FIGS.13 to 19. The resin magnet 68 illustrated here has, for example, eightmagnetic poles. The resin magnet 68 includes a plurality of taperednotches 68 b, each arranged substantially at a regular interval in thecircumferential direction on the inner periphery side of an end faceopposite to the side of the impeller attachment unit 67 a. That is, thenotches 68 b are formed on the inner periphery of the end face and areaxially extended from the end face by a predetermined length. In theexample illustrated in FIG. 15, there are eight notches 68 b. The notch68 b has a tapered shape with a diameter increasing on the end face sidecompared to the axial center side. The notches 67 d of the resin portion67 (refer to FIG. 11) are formed at the same positions as the fournotches 68 b arranged substantially at an interval of 90 degrees.

The resin magnet 68 includes a plurality of protrusions 68 a, eachbeing, for example, substantially horn shaped and extending axially by apredetermined length substantially at a regular interval in thecircumferential direction on an inner periphery side at a predetermineddepth from the end face opposite to the side where the notches 68 b areformed. In the example illustrated in FIG. 14, there are threeprotrusions 68 a.

As illustrated in FIG. 14, each protrusion 68 a has a convex portion 68a-1 that is substantially horn shapes when viewed from the side andprotrudes toward the end face. When the rotor unit 60 a is moldedintegrally, the convex portion 68 a-1 provided at the end of theprotrusion 68 a is held by the thermoplastic resin (the resin portion67) that forms the rotor unit 60 a. Accordingly, even if a slight gap isformed between the resin portion 67 and the resin magnet 68 due to resinshrinkage, the rotation torque of the resin magnet 68 can be reliablytransmitted, thereby enabling the quality of the rotor unit 60 a to beimproved. The shape of the protrusion 68 a is not limited to beingsubstantially horn shaped, and can be any shape such as a triangle,trapezoid, semicircle, circular arc, or polygon.

The resin magnet 68 includes a plurality of gates 68 c on the end faceon the side of the magnetic-pole position detection element (the Hallelement 58 b (see FIG. 4)). Each of the gates 68 c is molded into therotor 60 (see FIG. 15) and each of the gates 68 c is supplied with aplastic magnet (a material of the resin magnet 68). Note that the endface on the side of the magnetic-pole position detection element is anend face opposing the magnetic-pole position detection element fromamong the end faces of the resin magnet 68. The position of the gate 68c is, for example, at a magnetic pole center (see FIG. 15). By havingthe gate 68 c at the magnetic pole center, orientation accuracy of theresin magnet 68 can be improved.

As illustrated in FIG. 13, a hollow portion of the resin magnet 68 has astraight shape from the end face where the protrusions 68 a are formedto the substantially center position in the axial direction (thestructural center position in the axis direction) and has a drawing-outtaper shape from the end face opposite to the end face where theprotrusions 68 a are formed to the substantially center position in theaxial direction. Accordingly, the molded article can be easily taken outfrom the die, thereby enabling the productivity of the resin magnet 68to be improved and the production cost to be reduced. That is, becausethe hollow portion of the resin magnet 68 has a drawn-out taper shape,it can be prevented that a part of or whole of the molded article isstuck to the die and is hard to taken out (adhesion to the die), therebyenabling the productivity of the resin magnet 68 to be improved. The diefor molding the resin magnet 68 is divided into a fixed die and amovable die on the end face on the drawn-out taper side of theprotrusion 68 a. Because a part of the hollow portion formed by themovable die has a straight shape, sticking to the fixed die can beprevented further, and the productivity of the resin magnet 68 can beimproved. The resin magnet 68 is pushed out from the movable die by anejector pin.

As illustrated in FIGS. 13 to 15, a plurality (eight in the exampleillustrated in FIG. 15) of through holes 69, each extending in the axialdirection from the end face on the side of the magnetic-pole positiondetection element (the Hall element 58 b) to the end face on the side ofthe impeller attachment unit, are formed in the resin magnet 68, eachsubstantially on the same circumference. The through hole 69 is, forexample, a circular shape in cross section. The cross-sectional shape ofthe through hole 69 is not limited to a circular shape, and can be anyshape such as a triangle, trapezoid, semicircle, H-shape, crescent, orpolygonal shape (not illustrated).

As illustrated in FIGS. 14 and 15, the through holes 69 are respectivelyformed between the magnetic poles formed in the rotor 60. By forming thethrough holes 69 between the magnetic poles, the decrease in themagnetic force is reduced as much as possible, and thus a performancedecrease of the pump 10 can be reduced.

As illustrated in FIG. 15, a plurality (eight in the example illustratedin FIG. 15) of protrusions 68 e, having a substantially elongated holeshape in cross section, are radially formed on the end face opposite tothe magnetic-pole position detection element (the Hall element 58 b) ofthe resin magnet 68.

As illustrated in FIG. 15, the protrusions 68 e formed on the side ofthe magnetic-pole position detection element (the Hall element 58 b) areformed, for example, substantially at the center of the magnetic polesformed in the rotor 60. That is, the protrusions 68 e are arrangedcorresponding to the positions of the gates 68 c, to each of which thematerial of the resin magnet 68 is supplied. Further, the protrusions 68e, a plurality thereof (for example, eight in the example illustrated inFIG. 15), are formed on the same circumference. By providing theprotrusions 68 e at the magnetic pole center, the magnetic force isimproved and the performance of the pump 10 can be improved.

When the rotor unit 60 a is integrally molded from the thermoplasticresin (the resin portion 67), the through holes 69 and the protrusions68 e are embedded in the thermoplastic resin (the resin portion 67), andthe resin magnet 68 is held in the resin portion 67.

The resin magnet 68 is provided with a rotor-position detectingmagnetic-pole portion 68 f, which protrudes axially with a predeterminedheight in an annular shape having a predetermined width in a radialdirection (refer to FIGS. 13, 15, 17 and 19), on an outer periphery ofthe end face on the magnetic-pole position detection element (the Hallelement 58 b). In this manner, by causing a part of the resin magnet 68to protrude toward the magnetic-pole position detection element (theHall element 58 b) as the rotor-position detecting magnetic-pole portion68 f so as to reduce the axial distance between the rotor-positiondetecting magnetic-pole portion 68 f of the resin magnet 68 and the Hallelement 58 b mounted on the substrate 58, the detection accuracy of themagnetic pole position can be improved.

As the magnetic-pole position detection element, the Hall element 58 bbeing a magnetic sensor is used as the magnetic-pole position detectionelement, and the Hall element 58 b is packaged together with an IC thatconverts an output signal thereof to a digital signal and is configuredas a Hall IC, and the Hall IC is surface-mounted on the substrate 58. Byusing the Hall IC surface-mounted on the substrate 58 to detect leakageflux of the resin magnet 68 from the axial end face (the surfaceopposite to the magnetic-pole position detection element) of the resinmagnet 68, the machining cost and the like of the substrate 58 canreduce the production cost of the pump 10, as compared to a case wherethe Hall element 58 b is fixed to the substrate 58 by a Hall elementholder (not illustrated) so as to detect the main magnetic flux of theresin magnet 68 from the side surface of the resin magnet 68. Incontrast, in the conventional arts, in order to detect the magnetic poleposition, it has been necessary to assemble the magnetic-pole positiondetection element on the substrate by using a magnetic-pole positiondetection-element holder so that the magnetic-pole position detectionelement (the magnetic sensor) is positioned on an outer periphery of aposition detection magnet. Therefore, there have been problems inensuring an installation space of the magnetic-pole position detectionelement so as to increase the machining cost due to an increase in thenumber of components such as the magnetic-pole positiondetection-element holder.

Although not illustrated, as another modification of the resin magnet68, the position of the gate 68 c, to which the material of the resinmagnet 68 is supplied, can be arranged at the magnetic pole center. Inthis case, the gate 68 c can be provided in the protrusion 68 e. Theresin magnet 68 according to this modification can improve orientationaccuracy of the resin magnet 68 by positioning the gate 68 c at themagnetic pole center, thereby enabling the quality of the pump 10 to beimproved.

Integral molding of the rotor 60 of the pump motor by the thermoplasticresin is described next. The resin magnet 68 is an example of themagnet.

The die for integrally molding the resin magnet 68 and the sleevebearing 66 includes an upper die and a lower die (not illustrated). Thesleeve bearing 66 is first set in the lower die. The sleeve bearing 66can be set to the die without matching the circumferential direction,because the cross-sectional shape is symmetrical. The sleeve bearing 66includes a plurality of protrusions 66 a (refer to FIG. 12) on the outerperiphery thereof, but the position of the protrusions 66 a is notspecifically limited. Therefore, an operation process is simplified soas to improve the productivity, and the production cost can be reduced.

When the sleeve bearing 66 is set in the lower die, the inner diameterof the sleeve bearing 66 is held in a sleeve-bearing insertion portion(not illustrated) provided in the lower die, thereby ensuring theaccuracy of concentricity of the sleeve bearing 66 and the resin magnet68 to be set in a subsequent process.

After the sleeve bearing 66 is set in the lower die, the resin magnet 68is set in the lower die by fitting the tapered notches 68 b provided onthe inner peripheral edge of one of the end faces (the end face oppositeto the impeller attachment unit 67 a in the state of the rotor 60) tothe positioning protrusions (not illustrated) provided in the lower die.In the example illustrated in FIG. 15, there are eight notches 68 b.Four notches among these, provided substantially at an interval of 90degrees, are fitted to the positioning protrusions (not illustrated) inthe lower die, thereby ensuring the accuracy of concentricity of thesleeve bearing 66 and the resin magnet 68. The reason why the eightnotches 68 b are provided is to improve the workability at the time ofsetting the resin magnet 68 in the lower die.

Further, the magnet pressing parts (not illustrated) provided in theupper die are axially pressed against the substantially horn-shapedprotrusions 68 a formed on an inner peripheral edge of the other endface (the end face on the side of the impeller attachment unit, and inthe state of the rotor 60) of the resin magnet 68. Accordingly, thepositioning relation between the sleeve bearing 66 and the resin magnet68 is secured.

In the example illustrated in FIG. 14, three substantially horn-shapedprotrusions 68 a are provided on the inner periphery of the resin magnet68; and a die installation surface (a portion pressed by the die) of theprotrusion 68 a is exposed after integrally being molded. The reason whythere are three protrusions 68 a is to secure the positioning accuracyof the resin magnet 68 and ensure a flow passage of the thermoplasticresin to be used for integral molding, thereby alleviating the moldingcondition at the time of integral molding to improve the productivity.

Even when there is a gap between an insertion portion (not illustrated)of the resin magnet 68 in the lower die and the outer diameter of theresin magnet 68, an inner-diameter pressing part (the positioningprotrusion) provided in the lower die ensures the concentricity, and theposition relation and the concentricity between the sleeve bearing 66and the resin magnet 68 can be ensured by sandwiching these by the upperdie and the lower die, thereby enabling the quality of the pump 10 to beimproved.

In contrast, by making a gap between the insertion portion (notillustrated) of the resin magnet 68 in the lower die and the outerdiameter of the resin magnet 68, the workability at the time of settingthe resin magnet 68 in the die is improved so as to reduce theproduction cost.

After the resin magnet 68 and the sleeve bearing 66 are set in the die,the thermoplastic resin such as PPE (polyphenylene ether) is injectedinto the die, thereby forming the rotor unit 60 a. During the injection,the notches 68 b (FIG. 15) of the resin magnet 68 that are not pressedby the die, which are the four notches 68 and the protrusions 68 eprovided on the end face on the side of the magnetic-pole positiondetection element of the resin magnet 68, are embedded in the resinportion 67 of the thermoplastic resin so as to become a transmittingportion of the rotation torque. Further, through holes 69 and theprotrusions 68 e are embedded in the resin portion 67 of thethermoplastic resin, thereby firmly holding the resin magnet 68.

After the resin magnet 68 and the sleeve bearing 66 have been integrallymolded by using the thermoplastic resin (the resin portion 67), at thetime of magnetizing the resin magnet 68, highly accurate magnetizationcan be performed by using the notches 67 d (four notches in FIG. 11)formed on the inner periphery of the one end face in the axial directionof the resin magnet 68 for positioning at the time of magnetization.

The manufacturing process of the pump 10 is described next withreference to FIG. 20. FIG. 20 illustrates the manufacturing process ofthe pump 10.

(1) Step 1: The annular stator iron core 54 is formed by punching anelectromagnetic steel plate having a thickness of about 0.1 millimeterto 0.7 millimeter in a belt-like form and then being laminated byswaging, welding, or bonding. The sleeve bearing 66 is made as well. Inaddition, the resin magnet 68 having the through holes 69 extending inthe axial direction from the end face on the side of the magnetic-poleposition detection element (the Hall element 58 b) to the end face onthe side of the impeller attachment unit are molded.(2) Step 2: The stator iron core 54 is wound with a winding wire. Theinsulation part 56 using the thermoplastic resin such as PBT(polybutylene terephthalate) is applied to the teeth of the annularstator iron core 54 connected with the thin connection part. Theconcentratedly wound coil 57 is wound around the teeth applied with theinsulation part 56. For example, if 12 (twelve) concentratedly woundcoils 57 are connected, three-phase single Y-connection windings areformed. Because the winding is three-phase single Y-connection, theterminals 59 (the supply terminals to which power is supplied and theneutral terminal) of the stator 47, to which the coils 57 of respectivephases (a U phase, a V phase, and a W phase) are connected, areassembled on the connection side of the insulation part 56. Thesubstrate 58 is manufactured as well. The substrate 58 is held betweenthe substrate pressing component 95 and the insulation part 56. The ICthat drives a motor (for example, a brushless DC motor), the Hallelement 58 b that detects the position of the rotor 60, and the like aremounted on the substrate 58. Further, the substrate 58 is fitted withthe lead-wire leading component 61 that leads out the lead wire 52 atthe notched portion near the outer periphery thereof. The rotor unit 60a is manufactured as well. In the rotor unit 60 a, the ring-shaped(cylindrical or annular) resin magnet 68 molded by using the pelletformed by kneading a magnetic powder, for example, ferrite powder andresin and the cylindrical sleeve bearing 66 (for example, made ofcarbon) provided inside of the resin magnet 68 are integrally molded byusing the resin such as PPE (polyphenylene ether); and the through hole69 is embedded in the resin. The impeller 60 b is also molded. Theimpeller 60 b is molded by using the thermoplastic resin such as PPE(polyphenylene ether).(3) Step 3: The substrate 58 is to be assembled on the stator 47. Thesubstrate 58 fitted with the lead-wire leading component 61 is fixed tothe insulation part 56 by the substrate pressing component 95. Theimpeller 60 b is also assembled on the rotor unit 60 a by ultrasonicwelding or the like. The cup-shaped partition component 90 is alsomolded. The shaft 70 and the thrust bearing 71 are manufactured. Theshaft 70 is manufactured from, for example, SUS. The thrust bearing 71is manufactured from, for example, ceramics.(4) Step 4: The substrate 58 is soldered. The terminals 59 (the supplyterminals to which power is supplied and the neutral terminal) aresoldered to the substrate 58. The pilot hole component 81 is molded. Thecasing 41 is also molded. The casing 41 is molded by using athermoplastic resin such as PPS (polyphenylene sulfide). The rotor 60and the like are assembled into the cup-shaped partition component 90.(5) Step 5: After having manufactured the stator assembly 49 byassembling the pilot hole component 81 in the stator 47, the statorassembly 49 is mold-formed so as to manufacture the molded stator 50.The casing 41 is fixed to the cup-shaped partition component 90 toassemble the pump unit 40. The tapping screws 160 are also manufactured.(6) Step 6: The pump 10 is assembled. The pump unit 40 is assembled onthe molded stator 50 and fixed with the tapping screws 160 (refer toFIG. 2).

FIG. 21 is a conceptual diagram illustrating a circuit of arefrigeration cycle device using the refrigerant-water heat exchanger 2.The heat-pump type water heater 300 described above is an example of therefrigeration cycle device using the refrigerant-water heat exchanger 2.

The refrigeration cycle device using the refrigerant-water heatexchanger 2 includes, for example, an air conditioner, a floor heatingdevice, or a hot water dispenser. The pump 10 according to the presentembodiment constitutes a water circuit of a device using therefrigerant-water heat exchanger 2, and circulates water (hot water)cooled or heated by the refrigerant-water heat exchanger 2 in the watercircuit.

The refrigeration cycle device illustrated in FIG. 21 includes therefrigerant circuit having a compressor 1 (for example, a scrollcompressor or a rotary compressor) that compresses the refrigerant, therefrigerant-water heat exchanger 2 that performs heat exchange betweenthe refrigerant and water, the evaporator 4 (heat exchanger), and thelike. The refrigeration cycle device also includes the water circuithaving the pump 10, the refrigerant-water heat exchanger 2, a load 20,and the like.

As described above, according to the present embodiment, the followingeffects can be achieved.

(1) The resin magnet 68 integrally molded with the sleeve bearing 66 inthe rotor unit 60 a includes the plurality of through holes 69, eachextending in the axial direction from the end face on the side of themagnetic-pole position detection element toward the side of the impellerattachment unit and each substantially on the same circumference; thesethrough holes 69 are embedded in the thermoplastic resin when integrallymolded from the thermoplastic resin; and the resin magnet 68 is firmlyheld by the thermoplastic resin. Accordingly, cracking of the magnetsdue to the thermal shock associated with the cold/hot water cycle can bereduced.(2) Because the resin magnet 68 is firmly held by the thermoplasticresin without covering the outer peripheral surface of the resin magnet68 with the thermoplastic resin, the resin magnet 68 and the stator 47can be arranged close to each other, thereby enabling the performance ofthe pump 10 to improve.(3) Because the resin magnet 68 is firmly held by the thermoplasticresin without covering the outer peripheral surface of the resin magnet68 with the thermoplastic resin, the amount of thermoplastic resin usedcan be reduced, and the pump 10 can be manufactured at a lower cost.(4) Because the resin magnet 68 is firmly held by the thermoplasticresin without covering the outer peripheral surface of the resin magnet68 with the thermoplastic resin, irregularities, which cause an increaseof fluid friction losses, are not formed on the outer peripheral surfaceof the rotor 60, thereby enabling the performance of the pump 10 toimprove.(5) The through holes 69 provided in the resin magnet 68 are positionedbetween the magnetic poles formed in the rotor 60, so that a decrease ofthe magnetic force is much reduced and a performance decrease of thepump 10 can be reduced.(6) The resin magnet 68 is provided with the gates 68 c, to which thematerial of the resin magnet 68 is supplied, on the end face opposite tothe magnetic-pole position detection element (the Hall element 58 b);and because the position of the gate 68 c is at the center of themagnetic pole, the orientation accuracy of the resin magnet 68 can beimproved.(7) The plurality of protrusions 68 e are formed, each on the samecircumference substantially at a regular interval in the circumferentialdirection and on the end face opposite to the magnetic-pole positiondetection element (the Hall element 58 b) of the resin magnet 68, andthese protrusions 68 e are arranged at the center of the magnetic poles.Accordingly, the magnetic force is improved, thereby enabling theperformance of the pump 10 to be improved.(8) The hollow portion of the resin magnet 68 has a straight shape fromthe end face where the protrusions 68 a are formed to the substantiallyaxial center position; and has a drawn-out taper shape from the end faceopposite to the end face where the protrusions 68 a are formed to thesubstantially axial center position, thereby enabling the productivityof the resin magnet 68 to be improved.(9) When the pump 10 is applied to the refrigeration cycle device usingthe refrigerant-water heat exchanger 2 (for example, an air conditioner,a floor heating device, or a hot water dispenser), the performance andquality of the refrigeration cycle device can be improved and cost canbe reduced, due to the improvement of the performance, quality, and theproductivity of the pump 10.

Second Embodiment

FIG. 22 is a cross-sectional view of the rotor unit 60 a according tothe present embodiment, which corresponds to FIG. 9 described in thefirst embodiment. FIG. 23 is a cross-sectional view of the resin magnet68 according to the present embodiment, which corresponds to FIG. 13described in the first embodiment. In FIGS. 22 and 23, like referencesigns denote like constituent elements in FIGS. 9 and 13. In the presentembodiment, the through hole 69 according to the first embodiment isreplaced with a through hole 69 a having a shape as illustrated in FIGS.22 and 23. Other configurations are the same as those of the firstembodiment.

As illustrated by FIGS. 22 and 23, with a position (gradient changingposition) that is a set depth from the end face of the side with themagnetic-pole position detection element (the Hall element 58 b) as areference point, the inner diameter of the through hole 69 slopes, withincreasing gradients (diameters) (D1, D2), respectively, from thereference point towards both the magnetic-pole position detectionelement side and the impellor attachment unit side. That is, thecross-sectional shape of the through hole 69 a is such that the externalshape of the through hole 69 a on the opposite sides has the gradient D1with respect to the axial direction from the gradient changing positionto the end face on the side of the magnetic-pole position detectionelement so that the inner diameter of the through hole 69 a increasestoward the side of the magnetic-pole position detection element; and theexternal shape of the through hole 69 a on the opposite sides has thegradient D2 with respect to the axial direction from the gradientchanging position to the end face on the side of the impeller attachmentunit so that the inner diameter of the through hole 69 a increasestoward the side of the impeller attachment unit.

Further, by defining a gradient angle and a length of the through hole69 a so that the magnet volume on the side of the magnetic-pole positiondetection element becomes larger than that on the side of the impellerattachment unit, which is with reference to the center position of theresin magnet 68 in the axial direction (a structure center position inthe axial direction), the center of magnetic flux in the axial directionof the resin magnet 68 can be shifted by a predetermined distance towardthe side of the magnetic-pole position detection element. By shiftingthe center positions of the magnetic flux in the axial direction of therotor 60 and the stator 47 toward the side of the magnetic-pole positiondetection element, even in a case where the center position of the resinmagnet 68 in the axial direction and the center position of the stator47 in the axial direction are substantially the same, a propulsive forcefrom the side of the magnetic-pole position detection element toward theside of the impeller attachment unit is generated in the rotor 60 sothat the center positions of the magnetic flux in the axial direction ofthe rotor 60 and the stator 47 become substantially the same. Due tosuch a propulsive force of the rotor 60 pressing the rotor 60 againstthe casing 41 via the thrust bearing 71, fluctuations in the position inthe axial direction of the rotor 60 caused by pressure pulsation of thefluid due to the action of the impeller 60 b can be reduced, therebyenabling the quality of the pump 10 to improve.

Instead of providing the gradient in the through hole 69 a, by changingthe inner diameter of the through hole 69 a on the basis of thereference position at the predetermined depth from the end face of theresin magnet 68 on the side of the magnetic-pole position detectionelement, the center position of the magnetic flux in the axial directionof the resin magnet 68 can be shifted toward the side of themagnetic-pole position detection element by a predetermined distance(not illustrated).

According to the present embodiment, in addition to the effects of (1)to (9) described in the first embodiment, the following effects can beachieved.

(10) The through hole 69 a provided in the resin magnet 68 has agradient by which the inner diameter of the through hole 69 a increasesboth toward the side of the magnetic-pole position detection element andtoward the side of the impeller attachment unit, which is with referenceto the reference position at the predetermined depth (the gradientchanging position) from the end face on the side of the magnetic-poleposition detection element (the Hall element 58 b). Accordingly,adhesion to the die can be prevented, thereby enabling the productivityof the resin magnet 68 to improve.(11) By defining the gradient angle and the length of the through hole69 a so that the magnet volume on the side of the magnetic-pole positiondetection element becomes larger than the magnet volume on the side ofthe impeller attachment unit, which is with reference to the centerposition in the axis direction of the resin magnet 68, the center of themagnetic flux in the axial direction of the resin magnet 68 is shiftedby the predetermined distance toward the side of the magnetic-poleposition detection element. Accordingly, the propulsive force from theside of the magnetic-pole position detection element toward the side ofthe impeller attachment unit is generated in the rotor 60 to press therotor 60 against the casing 41 via the thrust bearing 71, therebyenabling the rotor 60 to reduce fluctuations of the position in theaxial direction caused by the pulsation of the fluid due to the actionof the impeller 60 b and enabling the quality of the pump 10 to beimproved.

INDUSTRIAL APPLICABILITY

As explained above, the present invention is useful as a pump, a methodfor manufacturing a pump, and a refrigeration cycle device.

REFERENCE SIGNS LIST

1 compressor, 2 refrigerant-water heat exchanger, 3 decompressiondevice, 4 evaporator, 5 pressure detection device, 6 fan motor, 7 fan, 8boiling-up temperature detection unit, 9 feed-water temperaturedetection unit, 10 pump, 11 operating unit, tank-unit control unit, 13heat-pump-unit control unit, 14 hot water tank, 15 refrigerant pipe, 16hot-water circulating pipe, 17 ambient-air temperature detection unit,20 load, 31 bathwater-reheating heat exchanger, 32 bathwater circulatingdevice, 33 mixing valve, 34 in-tank water-temperature detection unit, 35reheated water-temperature detection unit, 36 mixed water-temperaturedetection unit, 37 bathwater reheating pipe, 40 pump unit, casing, 42intake, 43 discharge outlet, 44 boss, 44 a screw hole, 46 shaft supportportion, 47 stator, 49 stator assembly, 50 molded stator, 52 lead wire,53 mold resin, 54 stator iron core, 54 a groove, 56 insulation part, 57coil, 58 substrate, 58 a IC, 58 b Hall element, terminal, 60 rotor, 60 arotor unit, 60 b impeller, 61 lead-wire leading component, 63 flatpump-unit installation surface, 66 sleeve bearing, 66 a protrusion,resin portion, 67 a impeller attachment unit, 67 b depression, 67 cimpeller positioning hole, 67 d notch, 67 e gate, 68 resin magnet, 68 aprotrusion, 68 a-1 convex portion, 68 b notch, 68 c gate, 68 eprotrusion, 68 f rotor-position detecting magnetic-pole portion, 69, 69a through hole, 70 shaft, 71 thrust bearing, 80 O-ring, pilot holecomponent, 82 die pressing part, 83 protrusion, 84 pilot hole, 85 legpart, 85 a protrusion, 87 connection part, 90 cup-shaped partitioncomponent, 90 a cup-shaped partition wall portion, 90 b flange portion,90 c circular )-ring housing groove, 90 d hole, 92 rib, 94 shaft supportportion, 95 substrate pressing component, 95 a protrusion, 100 heat pumpunit, 160 tapping screw, 200 tank unit, 300 heat-pump type water heater

1-10. (canceled)
 11. A motor rotor comprising: an annular magnet; and aresin portion formed from a thermoplastic resin from which is made anintegral molding for a rotor unit including the magnet, wherein themagnet includes a plurality of through holes that each extend in anaxial direction, and each of the through holes is embedded in thethermoplastic resin.
 12. The motor rotor according to claim 11, whereinone end face is in the axial direction of the magnet and opposes amagnetic-pole position detection element provided in a stator, and aninner diameter of each of the through holes increases toward a side ofthe magnetic-pole position detection element from a gradient changingposition that is a reference position at a certain depth from an endface on the side of the magnetic-pole position detection element of themagnet, and increases from the gradient changing position toward anopposite side to the side of the magnetic-pole position detectionelement.
 13. The motor rotor according to claim 12, wherein a gradientangle and a length of each of the through holes is defined so that amagnet volume on the side of the magnetic-pole position detectionelement from a central position in the axial direction of the magnet islarger than a magnet volume on an opposite side to the side of themagnetic-pole position detection element from the central position. 14.The motor rotor according to claim 11, wherein the plurality of throughholes are arranged such that each of the through holes is on a samecircumference, and each of the through holes is provided betweenmagnetic poles formed in the motor rotor.
 15. The motor rotor accordingto claim 11, wherein one end face is in the axial direction of themagnet and opposes a magnetic-pole position detection element providedin a stator, the magnet is a resin magnet, and gates, through each ofwhich a material of the resin magnet is supplied to each center ofmagnetic poles formed in the motor rotor, are provided on an end face ona side of the magnetic-pole position detection element of the magnet.16. The motor rotor according to claim 11, wherein one end face is inthe axial direction of the magnet and opposes a magnetic-pole positiondetection element provided in a stator, and the magnet is provided withprotrusions, each of which is arranged on a same circumference and at acenter of each of the magnetic poles formed in the motor rotor, on anend face on a side of the magnetic-pole position detection element. 17.The motor rotor according to claim 11, wherein one end face is in theaxial direction of the magnet and opposes a magnetic-pole positiondetection element provided in a stator, and the magnet is provided witha plurality of protrusions, each of which has a horn shape in crosssection and extends in the axial direction toward an opposite side to aside of the magnetic-pole position detection element, on an innerperiphery side at a certain depth from an end face that is on theopposite side to the side of the magnetic-pole position detectionelement.
 18. The motor rotor according to claim 11, wherein one end faceis in the axial direction of the magnet and opposes a magnetic-poleposition detection element provided in a stator, and the magnet isprovided with a plurality of notches, each of which has a substantiallyhorn shape in cross section and each of the notches is substantially ata regular interval in a circumferential direction, on an inner peripheryside of an end face on a side of the magnetic-pole position detectionelement.
 19. A motor comprising the motor rotor and the stator accordingto claim
 11. 20. A pump comprising the motor according to claim
 19. 21.A refrigeration cycle device comprising: a refrigerant circuit; a watercircuit; and a refrigerant-water heat exchanger that exchanges heatbetween a refrigerant and water by connecting the refrigerant circuitand the water circuit, wherein the water circuit includes the pumpaccording to claim 20.